1. Field of the Invention
The present invention relates to a centrifugal impeller having both a forward flow path and a rearward flow path for driving a fluid such as a gas or a liquid in two different directions, and more specifically to an impeller used in a small gas turbine engine in the compressor section.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Centrifugal impellers are well known in the art of pumps used to pump a fluid such as a liquid or a gas. In a centrifugal impeller, a plurality of closed fluid paths is formed between an inner surface and an outer surface of the impeller. A common inlet located upstream of the plurality of closed fluid paths allows for the fluid to enter the impeller and then be divided up into the plurality of flow paths. Each flow path includes an exit to discharge the fluid from the impeller. Rotation of the impeller acts to drive the fluid from the inlet, through the closed passages, and out the individual outlets. In all prior art impellers, the inventors of the present invention are not aware of any that disclose outlets in more than one direction.
Gas turbine engines are known to have a compressor to compress air to be delivered to a combustor, and a fan to provide a bypass to the combustor. In this arrangement, a fan for the bypass is a separate impeller than the compressor used to deliver pressurized air to the combustor.
It is a purpose of the present invention to provide for a centrifugal impeller that includes both a forward directed flow path and a rearward directed flow path.
It is another object of the present invention to provide for a gas turbine engine that has both a combustion flow path and a bypass flow path, in which the centrifugal impeller of the present invention provides for both the flow path into the combustion chamber and the flow path for the bypass of the fan.